Posttransplant recurrence of calcium oxalate crystals in pat
Primary hyperoxaluria (PH) is a metabolic defect that results in oxalate over-production by the liver and leads to kidney failure due to oxalate nephropathy. As oxalate tissue stores are mobilized after transplantation, the transplanted kidney is at risk of recurrent disease.

Researchers evaluated surveillance kidney transplant biopsies for recurrent calcium oxalate (CaOx) deposits in 37 kidney transplants (29 simultaneous kidneys and liver [K/L] transplants and 8 kidneys alone [K]) in 36 PH patients and 62 comparison transplants. The Median follow-up post-transplant was 9.2 years.

- Recurrence of CaOx crystals in surveillance biopsies in PH at any time post-transplant was 46% overall.

- Higher CaOx crystal index, which accounted for biopsy sample size, was associated with higher plasma and urine oxalate following transplant.

- There was a trend toward higher graft failure among PH patients with CaOx crystals on surveillance biopsies compared with those without. CaOx crystal deposition is frequent in kidney transplants in PH patients.

In particular, avoidance of high plasma oxalate and reduction of CaOx crystallization may decrease the risk of recurrent oxalate nephropathy following kidney transplantation in patients with PH.

American Journal of Transplantation